Proposal: sync Herdr themes with host terminal appearance

[lederniermagicien]

Related: #99 and #99 (comment)

Problem

Herdr can now expose host default colors to panes, but Herdr's own UI still needs a native appearance workflow: users who switch terminal/system themes need Herdr to follow without manually changing [theme].name.

Proposed direction

• Add [theme].appearance = "auto" | "dark" | "light".
• Keep existing [theme].name configs working.
• Add optional [theme].dark and [theme].light names for per-mode preferences.
• In auto, follow host terminal appearance/default-color changes.
• Proxy Mode 2031 / appearance queries so apps inside panes can follow the same changes.
• Add a Settings > Theme UI for appearance plus dark/light theme choices.

Draft branch

https://github.com/lederniermagicien/herdr/tree/feat/theme-appearance-sync

Local validation

• just check passed.
• Focused theme/settings tests passed.

Contribution intent

I would like maintainer feedback/approval before opening a PR.

[ogulcancelik]

[theme]
name = "terminal"

doesn't this solve your isse?

[lederniermagicien]

Hey @ogulcancelik , unfortunately not really :( Here's a screenshot in light/dark mode with your settings:


The dark mode is legible, but the light mode doesn't automatically change upon system appearance change.

My draft branch handles this by leveraging Mode 2031/996 + OSC 10/11 to automatically detect appearance changes from supported terminals (like Ghostty or whichever recent terminal) then adapt the theme dynamically on the go (without having to detach then launch again) and also an improved Theme menu with appearance selection + theme selection per mode:

Happy to rework/discuss the solution or even the approach itself!

[mjakl]

I came here because I stumbled over the need for detach/attach to get Herdr to respond with the updated OSC 11 after changing my system theme (currently Herdr responds with a cached core.host_terminal_theme and only updates in on attach). I've a Pi extension that changes the theme when the system theme changes, it relies on the OSC 11 response to detect changes.

I like the idea of being able to configure which theme applies for light/dark mode explicitly rather than relying on the terminal colors that aren't a good fit for my setup either. 👍

[progremir]

made my own topic and then saw yours. nice job!

[lederniermagicien]

Thanks both, hopefully this will be looked into when the dev has some spare time 😁

[ogulcancelik]

will be implemented soon, please track #675

[lederniermagicien]

Thank you 🙏😎